The use of mineral oil compositions containing a polyethylene polymer of specific properties in the formation of cable filler compositions and as splice compositions has been described, for example in U.S. Pat. No. 4,176,240 and U.S. Pat. No. 3,879,575. As described in U.S. Pat. No. 4,176,240, the contents of which are incorporated by reference herein, compositions for use as filling material can be prepared by admixing mineral oil, a styrene-ethylene butylene-styrene block copolymer, and a polyethylene which has a softening point of between 110.degree.-130.degree. C. Such compositions have been found to have improved handling characteristics over petroleum jelly-polyethylene cable filling materials.
As described in my copending application, Cable Filler Composition Containing Polypropylene, filed on even date herewith, a cable filling composition formed by admixing mineral oil, a styrene-ethylene butylene-styrene block copolymer, and an isotactic, crystalline polypropylene polymer having an average molecular weight of between 20,000 and 40,000, provides a composition having superior properties as compared with prior art compositions.
I have now found that the use of particular isotactic, crystalline polypropylene copolymers, with a minor amount of olefinic monomers, in cable filling compositions provides a composition having exceptional properties, as compared with prior art polyethylene containing compositions, and also as compound with polypropylene-containing compositions.